Tuesday, April 30, 2013
Exhibit Hall
Cellulosic ethanol, which has been the subject of significant technological progress, is produced from lignocellulose biomass. Utilization of such agricultural residues, for example wheat straw for industrial products has potential advantages. It is even more important for countries that lack abundant wood fiber. The wheat straw is characterized as fast-growing, moisture-loving, and shade-intolerant medium with a short life span. The chemical composition of wheat straw is characterized by its high cellulose content and low lignin content, making it an attractive biomass for fermentable sugar production. Organosolv pretreatment was applied to wheat straw using the acid-catalysis ethanol method to enhance sugar recovery in enzymatic hydrolysis. A Box-Behnken design (BBD) was used to optimize the effect of temperature, ratio of wood to liquor, ethanol concentration, and holding time on the pretreatment process. All variables except for lignin content were found to significantly affect the cellulosic yield as well as crystallinity index (CrI). Quadratic polynomial equations were used to model on the cellulosic yield, CrI, and lignin content for a regression analysis, using response surface methodology (RSM). The optimum process of organosolv pretreatment of wheat straw was found to be temperature 185 ºC, ratio of wood to liquor 1 to 4.2, ethanol concentration 45%, and holding time 41 min. The solid pretreated under optimum process conditions was evaluated for bioconversion using enzymatic hydrolysis of the cellulose fraction to glucose. Approximately 87% of the total cellulose was recovered as monomeric glucose after hydrolysis of the solid fraction.